The right of priority is claimed based on German Patent Application 100 44 379.6, filed Sep. 8, 2000, the disclosure of which is hereby incorporated by reference in its entirety.
1. Field of the Invention
The invention relates to a component for a motor vehicle and, in particular, to a cross member for the cockpit region of a motor vehicle.
2. Description of Related Art
The motor-vehicle industry has disclosed cross members which consist of pipes made of metal and having large wall thicknesses in order to provide sufficient resistance to bending, buckling and torsion, and hence sufficient pressure load-bearing capacity. These result in a high weight and disadvantages in terms of costs. Although, in principal, the pipes could be used for guiding air from, for example, an air conditioning system arranged centrally in the vehicle to lateral discharging means, such use has not been made to date since undesirable condensation water can easily be deposited on the metal pipes (see, for example, DE 197 53 877). Accordingly, although mentioned here, such cross members are not believed to relate to the same field of use as the present invention.
Furthermore, cross members are known which have a two-shell construction with webs welded into it for stabilization purposes. A cross member of this type is disclosed, for example, in DE 197 20 902. Cross members of this type are very expensive to produce and have a high weight. Guiding of air is not possible, and, as with the cross members referenced above, these cross members are mentioned here although they are not believed to relate to the same field of use as the present invention.
EP 0 370 342 discloses a lightweight component of a hybrid construction which can be used as a support in the motor vehicle and which has a shell-shaped base body which preferably is made of metal and in which reinforcing ribs are arranged. The reinforcing ribs are made of injected plastic and are connected to the metal base body at discrete connecting points by the plastic passing through apertures arranged in the metal part and extending beyond the surfaces of the apertures. The metal base body is of U-shaped design, and the reinforcing ribs pass through the interior of the base body in order to obtain high stiffness and strength. This known hybrid component has an advantageously low weight while at the same time having sufficient strength, stiffness and load-bearing capacity. Guiding of air is not possible by means of this lightweight component which can be used as a support. Accordingly, although mentioned here, such a cross member is not believed to relate to the same field of use as the present invention.
A cross member of the type mentioned at the beginning and having an air duct is disclosed, for example, in DE-U 299 16 466. In this type of construction, air guiding ducts are inserted below the plastic ribbed arrangement as a premanufactured, tubular structure after production of the cross member of a hybrid construction. Introducing a duct in this manner is costly and can only be carried out with difficulty.
An object of the invention is to provide an improved lightweight component into which a duct can be advantageously integrated.
In accomplishing the objects of the invention, there has been provided according to one aspect of the invention a cross member suitable for a motor vehicle comprising (a) a base body comprising a base, a first wall and a second wall arranged in a concave cross section; (b) a plastic reinforcing rib assembly injection molded on said base of said base body to stiffen said base body; (c) a plastic shell injection molded together with said plastic reinforcing rib assembly; bearing against the side of said base opposite to said plastic reinforcing rib assembly and extending in a longitudinal direction along at least a portion of the cross member; and (d) a cover covering said plastic shell and thereby defining a duct.
According to another aspect of the invention, there is provided a cross member as wherein said plastic reinforcing rib assembly comprises a first plastic web formed with said base body and extending, in the same plane as, but in the opposite direction from said first wall; and a second plastic web formed with said base body and extending in the same plane as, but in the opposite direction from said second wall, and plastic ribs extend between said first and second plastic webs.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows when considered together with the accompanying drawings.